Why Is Boiler Making Noise Until I Put On Hot Tap Then Quietens Down

[joanne2002]

Hi,
I have a worcester bosch 24i combi which is making a lot of noise. We have replaced the pump the pressure relief as it was all scaled up and stopped the dripping out the back wall with new valve. WHAT HAPPENS IF WE PUT ON HEATING MAKES A LOT OF NOISE NOT REALLY BANGING NOISES THOUGH AND IF I LET THE HOT TAP RUN IT GOES QUIET, last night it stayed quiet but tonight not so...Is it maybe the heat exchanger ? thanks in advance ( glad i found this site )....Jo

[The Builder]

Well Jo, as always ..... it could be a number of things. Simply having the circulating pump set too high can induce a banging noise. Also, a build up of sludge in the heat exchanger could do it. Flushing with a sludge remover should help that.
First thing to try is a good bleed. It could well be nothing more than an air lock.

[sherrardk]

Mine makes a terrible noise if the pressure thing is too low.

[The Builder]

That's another one, Sherrard.
Do check your system pressure gauge Jo.

[joanne2002]

yes its is .5 rising to 2 when in use....

[joanne2002]

i mean 1.5 !!!

[The Builder]

OK, rule that one out Jo. 1.5 is just right.

Try a bleed